regular expression

Question

1. What type of grammar is this most accurately described as?

S->b/ aD

D->a/ aDD

A. A regular grammar   B. CFG    C. CSG     D. Type-0

Answer 1

(B) Context Free Grammar

In CFG, if there is a production as $X\rightarrow Y $ then  $X \epsilon V$  and  $Y \epsilon (V +T)^*$